High voltage surge arresters are common in the field of electric power transmission and distribution. They may form part of a dissipative system by means of which currents are dissipated upon transient overvoltages occurring in an electric system. Such an arrester may comprise a plurality of varistor elements which, upon being subjected to a predetermined voltage, turns from a highly resistive state into an electrically conducting state. One end of the arrester may be connected to ground and the other end to an electric network. The varistor elements need to be electrically insulated and they are insulated as well as protected from the environment by means of an electrically insulating enclosure provided with sheds.
U.S. Pat. No. 8,305,184 B2 discloses a surge arrester and a mould in accordance with the preambles of the independent claims of the present patent application.
EP2444982 A1 discloses a shed for e.g. a surge arrester. The shed is shaped as a tapered disk with a curved free edge. In the embodiment of FIG. 9 of EP2444982 A1, the upper surface of the shed forms a blunt angle with respect to the longitudinal axis of the surge arrester whereas the lower surface extends perpendicularly from said axis.